procd: add SELinux support

This commit adds a patch to procd to support loading the SELinux
policy early at boot time, and adjusts the procd package to use this
SELinux support when libselinux is enabled.

The procd patch has been submitted separately [1]: obviously the
intent is to have it merged in the procd Git repository rather than
have it in OpenWrt itself.

[1] http://lists.infradead.org/pipermail/openwrt-devel/2019-November/025791.html

Signed-off-by: Thomas Petazzoni <[email protected]>
[rebase, add commit message]
Signed-off-by: W. Michael Petullo <[email protected]>
[split commit into openwrt.git and procd.git]
Signed-off-by: Daniel Golle <[email protected]>

package/system/procd/Makefile

@@ -12,9 +12,9 @@ PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/procd.git
-PKG_SOURCE_DATE:=2020-08-06
-PKG_SOURCE_VERSION:=ab55357dfe5bd0edac0b9556a83e69814df791b1
-PKG_MIRROR_HASH:=38c882e105811bcd10b5ce55f91a16a647ed2ad436aec01cd03fda588b7bfca9
+PKG_SOURCE_DATE:=2020-08-10
+PKG_SOURCE_VERSION:=fad899769e1411cc273785461f073a0f7931b9a0
+PKG_MIRROR_HASH:=f56b621f78f821f7070d85f63448f684af7e2fe0c85233a8d054683cc34f6d06
 CMAKE_INSTALL:=1
 
 PKG_LICENSE:=GPL-2.0
@@ -44,7 +44,7 @@ TARGET_LDFLAGS += -flto
 define Package/procd
   SECTION:=base
   CATEGORY:=Base system
-  DEPENDS:=+ubusd +ubus +libjson-script +ubox +USE_GLIBC:librt +libubox +libubus +libblobmsg-json +libjson-c
+  DEPENDS:=+ubusd +ubus +libjson-script +ubox +USE_GLIBC:librt +libubox +libubus +libblobmsg-json +libjson-c +PACKAGE_libselinux:libselinux
   TITLE:=OpenWrt system process manager
   USERID:=:dialout=20 :audio=29
 endef
@@ -108,7 +108,8 @@ ifdef CONFIG_PACKAGE_procd-ujail
 endif
 
 SECCOMP=$(if $(CONFIG_PACKAGE_procd-seccomp),1,0)
-CMAKE_OPTIONS += -DSECCOMP_SUPPORT=$(SECCOMP) -DUTRACE_SUPPORT=$(SECCOMP)
+SELINUX=$(if $(CONFIG_PACKAGE_libselinux),1,0)
+CMAKE_OPTIONS += -DSECCOMP_SUPPORT=$(SECCOMP) -DUTRACE_SUPPORT=$(SECCOMP) -DSELINUX=$(SELINUX)
 
 define Package/procd/install
 	$(INSTALL_DIR) $(1)/sbin $(1)/etc $(1)/lib/functions